With these pump devices the level of exudate fluid collected in a container must be monitored to ensure the container doesn't become completely filled. This is important to avoid the pump unit from becoming infected and to ensure the correct therapy is being applied. Due to the infectious nature of the exudate fluid and that the containers can be disposable it is a significant advantage to employ a non-contact fluid level detection method.
There are many techniques for measuring fluid levels including floats, contacts, ultrasound and light, but capacitive or electric field sensing has perhaps the most advantages for measuring wound exudate fluid levels. It is known to place conductive elements on the outside of a container connected to a circuit to detect any change in the capacitance of the capacitor formed thereby. The change in capacitance is due to the change in the dielectric constant of the combination of the container and fluid due to change in the fluid level therein. Such sensors are either ON or OFF and detect when the fluid reaches the level of the capacitance element. There is no availability to detect the fluid level at several points within a container or to track the flow of fluid.
The sensors also cannot differentiate between a fluid level within the container or drops spattered across the walls of the container.
Accordingly, the invention seeks to make improvements.